Power Sustainability: Grundfos Pumps Drive Africa's Largest Solar Irrigation Project
During several years of rolling blackouts in South Africa, the Mont Rouge Olive Estate struggled to irrigate its 200 hectares of olive trees. The issue was resolved through a setup that combines holding dams, a gravity-fed drip irrigation network, and 750 kWp of PV solar panels driving Grundfos pumps. “If all the farms in Africa went this route, it would be Utopia. Not only for Africa, but for the planet,” says owner Pieter Coetzee.
The Situation
Mont Rouge Olive Estate lies in the arid heart of South Africa’s Little Karoo, 26 kilometres down a dusty mountain road. Operated by Assegaay Bosch Ranch, it produces around 300,000 litres of olive oil annually from 120,000 trees spread across 200 hectares. Rainfall averages only 150 mm per year, but nearby Rooiberg mountains receive ten times that. Water from two rivers is collected into holding dams below the farm.
For over a decade, the challenge was getting that water to the trees reliably. Frequent “load shedding” and scheduled rolling blackouts lasting up to 12 hours meant the electric pumping system couldn’t operate consistently. Diesel-powered generators were a costly and unsustainable fallback. “If we didn’t take emergency measures, most of our groves would have died,” says Coetzee. “So we decided to move green.”
The Solution
The estate deployed South Africa’s most extensive single-axis tracking solar irrigation system to date. Three solar PV arrays (with a fourth underway) provide 750 kWp to Grundfos pumps stationed at holding dams. Daily, 3,000 m³ of river water is pumped into mid-slope storage dams and then to a large plateau dam at the highest farm point. The 50,000 m³ reservoir, equal to 20 Olympic pools, acts like a battery.
“If you’ve got height, you’ve got power,” says Coetzee. “Once water is stored up there, we simply open a valve and gravity does the work. It’s so simple, it’s laughable.”
This setup mimics the operation of a raw water treatment plant, efficiently managing untreated river water for use in large-scale drip irrigation. It reflects many of the same design principles used in modern raw water treatment plant installations for agriculture.
The System
“All 200 hectares of olive trees are irrigated using solar-powered pumps,” explains Hannes Van Niekerk, CEO of SAW Africa, the system designer. Initially, in cattle farms and small-scale irrigation, SAW Africa has used Grundfos solar pumps since 2002. Today, they design systems over 1 MW, “the sky’s the limit.”
Grundfos pumps operate using variable speed drives powered directly by solar panels. The system is off-grid but can function in hybrid mode if grid power is available. “This enables irrigation in places where power access is nonexistent,” says Gerrit-Jan Cronselaar, CTO of SAW Africa.
The solar panels are mounted on single-axis trackers that follow the sun, increasing energy production. “Instead of six hours, we now get 11 hours of full solar generation,” says Cronselaar. That extended production time allows for greater pump efficiency with lower peak demand. By switching from fixed-tilt PV panels to a single-axis tracking setup, the system now delivers up to 30% more water each day.
This innovative configuration functions as part of a broader set of water treatment plant components and essential water treatment components, including pumps, inverters, reservoirs, and gravity-fed irrigation systems.
The Outcome
Installed in 2021, the system brought major operational and sustainability improvements. “It’s clean, always available, and allows us to say we’re carbon neutral, maybe even carbon negative,” says Coetzee. “We produce more electricity than we consume.”
Maintenance has dropped significantly. Farm manager Marnus Dippenaar notes, “We used to have one or two pipe bursts every week due to vacuum and water hammer issues when pumps restarted after blackouts.” Since the solar system’s installation, just one pipe burst has occurred, and it was quickly resolved.
The holding dams also act as natural sedimentation tanks. “Sediment settles at the bottom,” explains Dippenaar, “so our drip lines get clean, soft water and rarely clog.” This sediment handling is an integral part of water treatment components in sustainable irrigation systems.
Grundfos Supplied
Grundfos supplied 12 pumps with scalable speed drives distributed across three pumping stations at each solar array. These include NK end suction pumps and a booster set with CR95 pumps. The system also includes Grundfos Renewable Solar Inverters (RSIs), which convert DC from solar panels into AC for pump operation.
Additionally, the system uses Grundfos Power Adapt, a control feature that automatically selects the best power source, solar or grid. This ensures uninterrupted operation even in hybrid setups. This functionality supports long-term system durability and flexibility.
Broader Impact on Agriculture
Applying this solar-powered irrigation system has far more implications than the Mont Rouge Olive Estate. Many African agricultural operations face water scarcity, inconsistent power supply, and increasing operational costs. Water availability is not just an advantage of transitioning to solar-driven systems, but also makes farming more financially viable in the long term.
As many rural areas lack grid stability, the success of Mont Rouge showcases how renewable technologies and reliable water treatment plant components, alongside other critical water treatment components, can support agricultural productivity without dependence on fossil fuels or erratic grid power. Farms that used to depend heavily on seasonal rainfall or costly diesel generators can now try solar irrigation as a practical and consistent solution.
Cost Efficiency and Return on Investment
While the initial setup costs of solar panels, water treatment plant components, and high-efficiency pumps can be significant, the return on investment becomes clear in just a few years. Farms can reinvest savings into expanding their operations, improving crop quality, or adding post-harvest processing units by removing costly diesel expenses and reducing the risk of devastating crop failure.
At Mont Rouge, the combination of energy independence and water reliability has directly translated into better olive yields and reduced overheads. Additionally, reducing overall operating complexity, automation has minimized labor-intensive maintenance.
Climate Resilience and Water Conservation
This model of sustainable irrigation contributes directly to climate resilience. Using gravity-fed drip systems from elevated storage reduces water loss due to evaporation and runoff, two major issues in conventional irrigation systems. More importantly, the holding dams function as both a buffer during dry spells and a natural pre-filtration basin, similar to the early-stage sediment control seen in raw water treatment plant components.
Solutions like Mont Rouge’s system will become more important as climate variability continues to impact rainfall patterns and groundwater levels. Integrating gravity-fed irrigation with solar-powered raw water treatment plant methods positions farms to better withstand droughts and maintain consistent output.
